Holmes thanked Dayton Flyers head coach Anthony Grant and assistant coach Ricardo Greer for the opportunity.
» MORE ON FLYERS: 2022 recruiting heats up
Holmes attended Millenium High School in Goodyear, Ariz., his first three years. He announced in May he would transfer to Montverde Academy, which is located near Orlando, Fla., for his final year.
Holmes averaged 23.5 points, 10.5 rebounds, 3.8 blocks and 3.1 assists as a junior and was named the Gatorade Player of the Year in Arizona.
Holmes has received offers from San Diego State and Arkansas in recent weeks. Arizona, UCLA and Virginia are among the many other schools to offer him scholarships.